Self-heated protective garment

ABSTRACT

A heat-augmentable outside garment for protecting personnel from extended low temperature exposure. A network of flexible tubing lined within the outside garment completes a loop between the one ends of two coils within chambers of a portable heater unit containing a chemical exothermic composition. The other ends of the coils are connected respectively to an upper and a lower chamber of a portable manual double-action pump. The upper and the lower chambers of the pump, the coils, and the tubing are filled by a heat transfer fluid. Reciprocation of the pump alternates fluid flow to and from the two coils and the tubing resulting in heat transfer from the exothermic reaction of a chemical composition to the garment.

United States Patent Esposito [451 June 20, 1972 [S4] SELF-HEATED PROTECTIVE GARMENT [72] inventor; Esposito,Delran,NJ. [73] Assignee: The United States of America as represented by the Secretary of the Navy.

3,536,059 10 1970 Hearst et al Primary Examiner-Charles J. Myhre Attorney-R. S. Sciascia and Henry Hansen ABSTRACT A heat-augmentable outside garment for protecting personnel from extended low temperature exposure. A network of flexible tubing lined within the outside garment completes a loop between the one ends of two coils within chambers of a portable heater unit containing a chemical exothennic composition. The other ends of the coils are connected respectively to an upper and a lower chamber of a portable manual doubleaction pump. The upper and the lower chambers of the pump, the coils, and the tubing are filled by a heat transfer fluid. Reciprocation of the pump alternates fluid flow to and from the two coils and the tubing resulting in heat transfer from the exothermic reaction of a chemical composition to the garment 7 China, 2 Drawing Figures PATENTEDJum 1972 I-"JE JOHN J. EsPoswo ATTORNEY SELF-HEATED PROTECTIVE GARMENT BACKGROUND OF THE INVENTION The present invention relates generally to thermal exposure protection systems, and more particularly to low temperature environment protective garments in combination with portable heat generating apparatus connected to the garment by a heat exchange system.

The protective systems for personnel from extended low temperature exposure may be identified as either passive or active. Protection is typically accomplished by a passive system with thickly insulated garments which limit the body heat loss to heat a balance level within the comfort limits of the wearer. Passive exposure protective garments are usually bulky and heavy and restrain the wearer's freedom of movement. Restricted movement is particularly prevalent around the limbs of the wearer where the heat loss surface to volume ratio is high thus requiring large amounts of insulation to maintain a comfortable local heat balance. Active systems of the prior art include an active heat source augmenting the heat generated by the wearer. A heat transfer fluid is circulated through a network of flexible tubing distributed within the garment by powered recirculation pumps continuously and unidirectionally pumping the fluid in a closed loop from an external heater to the tubing. The unidirectional circulation mode typically requires large heat transfer volumes when contemplating large heat sources to accommodate large temperature gradients in order to maintain an efiicient heat balance around the loop. To accommodate various degrees of environmental extremes, either an automatic or manual control is also included with the heater or the recirculation pumps. Thus, the active systems were complex as well as bulky and heavy and limited the wearer's mobility.

SUMMARY OF THE INVENTION Accordingly, it is the general purpose and object of the present invention to provide a heat-augmentated protective garment which is of relatively simple construction and which may be manually powered for fluid circulation.

Another object of the invention is to provide a personnel heat augmentation system which is adaptable to be conveniently incorporated into a diver's suit and that is compatible with a sea environment.

Briefly, these and other objects are accomplished according to the present invention by providing a portable chemical heat pack surrounding heat exchange coils attached at each end of a tubing network disposed within a protective garment together with a portable double action valveless pump connecting the other ends of the coils such that the heated fluid can be alternately passed from the pack into the tubing network where it dissipates the heat and then on demand in the other direction from the pack into the network displacing the cooled fluid back into the pack. The heat pack incorporates a chemical heat generator activated by water, which can be either sea water or fresh water, which upon combining with the chemicals contained in the pack produces an exothennic reaction. Thus the heat transfer fluid is heated continuously within the pack and is transferred to the tubing network in the garment by manual actuation of the pump on demand. In order to accommodate large temperature gradients across the garment it is contemplated to raise the root mean square level of temperature within the network without increasing heat transfer fluid volumes thus providing the added feature that within the heat pack the coil temperatures are periodically low thereby raising the thermal efficiency of the heat pack.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 represents a heat-augmentable garment with its portable heat pack and manual pump according to the invention worn by a subject; and

FIG. 2 is a more detailed schematical representation of the inventive garment and equipment of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIG. 1, an exposure garment 10 is shown together with a heater back pack unit 11 suspended by straps 12 at the upper back torso of the garment 10. Unit 11 is isolated from garment 10 by two insulation strips 13 disposed on either end thereof. Right and left flexible conduits 15 are connected between the upper end of unit 11 and respective shoulder fittings 14 on garment 10. At the bottom end of unit I] proximate the sides there are attached respectively right and left pump conduits 16 connected respectively at their distal ends to the upper and lower ends of a valveless pump 20 suspended from a belt 21 on the waist of garment 10. A manual handle 22 extends from the upper end of pump 20 where it is operable by the wearer.

As shown in FIG. 2, unit 11 includes right and left heat packs 25, each including a conductive tubing coil 26 terminating at the upper and lower ends of pack 25. Packs 25 are separated by a common wall 250 providing thermal isolation such that the alternate heat balance cycles taking place in the individual packs are separated, allowing for higher efficiency. Wall 25a may be deleted forming a single cavity containing both coils 26, however the thermal efficiency of the heat pack is thus reduced by the alternate cooling effect of the respective coils. Each pair of conduits l5 and I6 is attached respec-. tively to the upper and lower ends of the corresponding coil 26. A chemical composition 27 partly fills the cavity formed by pack 25 surrounding coil 26, composition 27 being of any type commonly known to those in the art that will produce an exothermic reaction upon combination with another chemical. It is desired, of course, that the chemicals before and after reaction be relatively safe to handle, and that the reaction produce an efficient heat transfer at a useful rate. For example, calcium chloride in the packs 25, with water as the other reactant, has been found suitable. The invention, however, is not limited to any particular selection or combination of reactants. An opening 28 is provided in the upper end of each pack 25 for the purpose of introducing the other reactant to activate the reaction. The remaining volume within the cavity formed by pack 25 forms a heat sink when filled with the other reactant thereby limiting the overall temperature within pack 25 to the boiling point of the reactor.

Conduits 16 complete one-half of a loop through pump 20 which is separated into upper and lower chambers by a piston 30 connected to a rod 31 slidably extending through the upper end of pump 20 and terminating with a handle 22. Conduits 15 are respectively connected to right and left shoulder fittings 14 in the garment 10. A flexible tubing network 35 is con tained within a lining 36 of garment I0 contiguously attached thereto forming parallel sections between the right and the left shoulders, the loop sections joining at the respective conduit 15 connections. The volumes contained within pump 20, conduits l5 and 16, tubing network 35 and coils 26 are filled with a heat exchange fluid of any type known in the art which is heated in the heat packs 25 and which dissipates heat within the garment 10. It is also contemplated that the displacement volume in the pump 20 be sufficient to cause all of the heat transfer fluid in flexible tubing network 35 to pass through either coil 26 for each stroke of piston 30.

In operation the wearer of the garment l0 activates the exothermic reactions within heat packs 25 by introducing a suitable reactant into openings 28 thereon. The exothermic reaction then heats the heat exchange fluid contained in coils 26. The wearer operates handle 22 either in an upward or a downward stroke thereby alternately moving the volume contained within right or left coil 26 into the flexible tubing network 35. Tubing network 35 gives off heat which both warms the wearer and is dissipated across the garment I0 surface. When the heat in the network 35 is dissipated to a point that the wearer notices discomfort he reverses the stroke of pump 20 introducing the heated fluid from the other coil 26 into the tubing network 35 thereby displacing the cooled volume in network 35 back into the first heating coil 26. The maximum temperature that can be generated within heating units 25 is determined by the boiling temperature of the reactor necessary for the reaction. Accordingly the heat exchange fluid contained in coils 26 can only be heated to 212 F. when the reactor is water. The thermal mass and resistance properties of the fabrics or materials used in the garment are selected such that the wearer is never exposed to temperaturesbeyond the tolerance limits of the human body.

Some of the many advantages of the foregoing invention should now be readily apparent. The invention provides a heat-augmentable garment which is both simple and reliable and-which may be activated by a reactant such as fresh or sea water which is usually available in areas where low temperature exposure is a hazard. The invention also provides the added advantage over the prior art in that it can accommodate an acceptable heat balance over a larger temperature gradient by combining double the total heat source without increasing the size of the heat transfer apparatus.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the ap pended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

l. A portable self-contained personal heat augmenting system for providing protection to a wearer in a low temperature environment comprising, in combination:

an outer garment enclosing the wearer;

heat distributing means disposed within the garment for distributing heat therein;

heat generating means supportable by a wearer of said garment and cooperating with said gannent, said heat generating means connected across said heat distributing means for providing a portable heat source;

heat transfer fluid operatively associated with said heat generating means and said heat distributing means;

a reciprocating dual action pump means supportable by a wearer of said garment and cooperating with said garment, said pump means cooperating with said heat generating means for moving, during each stroke thereof, a portion of the heat transfer fluid from said heat generating means through said heat distributing means, while simultaneously moving another portion of the fluid from the heat distributing means through the heat generating means; and

the thermal mass and resistance properties of the materials forming said garment being selected such that temperatures in said garment are maintained within the tolerance limits of the human body.

2. A personal heat augmenting system according to claim 1. in which said dual action pump means comprises a manually operated valveless pump.

3. A personal heat augmenting system according to claim 2, in which said heat generating means includes a heat pack containing exothermic reagents, two heat transmissive conduit means disposed within said heat pack the distal ends thereof extending out of said heat pack, and supply passageway means formed in said heat pack for supplying liquid reactant into engagement with said reagents whereby said exothennic reaction is activated.

4. A personal heat augmenting system according to claim 3, in which said heat transmissive conduit means each includes a conductive metallic coil formed to contain a volume of heat exchange fluid approximately equal to the volume contained within said heat distributing means of said garment.

5. A personal heat augmenting system according to claim 4, in which said heat distributing means includes a flexible tubing network disposed within said garment in parallel loop sections joined in common at the corresponding ends thereof and operatively connected at the ends thereof between the respective one ends of said coils.

6. A personal heat augmenting system according to claim 5,

in which said pump means includes a housing, a piston slidably contained in sealing engagement within said housing, actuation means slidably extending from said housing attached at one end thereof to said piston, passageways one at each end of the housing and hoses operatively connecting said passageways and respective other ends of said coils.

7. A personal heat augmenting system according to claim 6, in which said heat pack includes a thermally insulating dividing wall disposed between said coils, whereby the heat balance of each coil is partly separated from the other. 

1. A portable self-contained personal heat augmenting system for providing protection to a wearer in a low temperature environment comprising, in combination: an outer garment enclosing the wearer; heat distributing means disposed within the garment for distributing heat therein; heat generating means supportable by a wearer of said garment and cooperating with said garment, said heat generating means connected across said heat distributing means for providing a portable heat source; heat transfer fluid operatively associated with said heat generating means and said heat distributing means; a reciprocating dual action pump means supportable by a wearer of said garment and cooperating with said garment, said pump means cooperating with said heat generating means for moving, during each stroke thereof, a portion of the heat transfer fluid from said heat generating means through said heat distributing means, while simultaneously moving another portion of the fluid from the heat distributing means through the heat generating means; and the thermal mass and resistance properties of the materials forming said garment being selected such that temperatures in said garment are maintained within the tolerance limits of the human body.
 2. A personal heat augmenting system according to claim 1, in which said dual action pump means comprises a manually operated valveless pump.
 3. A personal heat augmenting system according to claim 2, in which said heat generating means includes a heat pack containing exothermic reagents, two heat transmissive conduit means disposed within said heat pack the distal ends thereof extending out of said heat pack, and supply passageway means formed in said heat pack for supplying liquid reactant into engagement with said reagents whereby said exothermic reaction is activated.
 4. A personal heat augmenting system according to claim 3, in which said heat transmissive conduit means each includes a conductive metallic coil formed to contain a volume of heat exchange fluid approximately equal to the volume contained within said heat distributing means of said garment.
 5. A personal heat augmenting system according to claim 4, in which said heat distributing means includes a flexible tubing network disposed within said garment in parallel loop sections joined in common at the corresponding ends thereof and operatively connected at the ends thereof between the respective one ends of said coils.
 6. A personal heat augmenting system according to claim 5, in which said pump means includes a housing, a piston slidably contained in sealing engagement within said housing, actuation means slidably extending from said housing attached at one end thereof to said piston, passageways one at each end of the housing and hoses operatively connecting said passageways and respective other ends of said coils.
 7. A personal heat augmenting system according to claim 6, in which said heat pack includes a thermally insulating dividing wall disposed between said coils, whereby the heat balance of each coil is partly separated from the other. 